Duplex-diaphragm horn or signal.



A. L. MCMURTRY.

DUPLEX DIAPHRAGM HORN 0R SIGNAL.

APPLICATION FILED JAN. 31, 1912.

1 14 91, Patented Au 3, 1915.

MW 1 Q4M%%% 9% I human STATES ALDEN L. MOMURTRY, OF SOUND. BEACH, CONNECTICUT, ASSIGNOR, IBY MESNE ASSIGN- MENTS, TO LOVELL-MGCONNELL MANUFACTURING COMPANY, A CORPORATION OF DELAWARE.

1,1&8,916.

To all whom it-may concern:

Be it known that I, ALDEN L. MCMURTRY, a citizen of the 'United States, and a resident of Sound Beach, county of Fairfield, State of Connecticut, have invented new and useful Improvements of Duplex-Diaphragm Horns or Signals, of which the following is a specification. I

My invention relates to that class of horn or signal wherein a vibratory diaphragm is actuated to produce a sound of the desired tone.

My invention involves the use of two diaphragms, a connecting chamber and a projector or resonator, the actuating means being located between them, and arranged to give a distinctive and pleasing sound. The resulting construction is especially advantageous because of its compactness, simplicity, and small number and accessibility of parts. If desired both diaphragms may be vibrated with the same rapidity to produce sounds of like pitch but with the vibrations produced by each amplified by those produced by the other. On the other hand it may be arranged that the diaphragms be vibrated at different rates, the periodicity of their vibrations being so predetermined and coordinated with each other and with the connecting chamber that the two different sounds produced shall harmonize.

In the drawings, herewith, wherein like reference characters denote like parts, I have for the purpose of simplifying the drawings, shown my invention as embodied in a. horn or signal adapted to be operated by hand.

Figure 1 represents a sectional view in side elevation of a horn embodying my invention. Fig. 2 represents a sectional View taken on line 22 of Fig. 1 in the direction indicated by the arrows thereon. Fig. 3 represents a sectional view taken on line 3-3 of Fig. 1 in the-direction indicated by 'the arrows thereon.

Turning to a detail description of my invention and considering the drawings in connection therewith, the casing 10 of the horn is in the form of a hollow tube the ends of which are oppositelycurved over and inward terminating in op osing open cup shaped end portions 11. ntrally of the length of the horn casing is formedan opening 12 provided with a pro ector 13, of

Specification of Letters Patent.

Patented Aug. 3, 1915.

Application filed January 31, 1912. Serial No. 674,585.

desired shape and size, secured to the casing. v\Vithin each of the open ends of the horn casing is seated a circular diaphragm 11 held in position by a retaining ring 15 screw threaded on. the inner surface of the casing. A shaft 16 extends midway between-the diaphragms, its axis being on a. line with their centers. Shaft 16 is journaled in bearings at the tops of the arms 1-7 of a supporting bracket secured to the horn casing. Between the bearings two toothed cog wheels 18 18 are mounted on shaft 16, the line of centers of the diaphragnis passing midway between thetwo cog wheels. On each diaphragm is mounted an anvil 19, securely aflixed thereto, the anvils projecting outwardly and being oppositely bent or inclined at their tops so that each anvil will contact with the teeth of one of the cog wheels. Shaft 16 and the cogs thereon are rotatable through power applied to the shaft in any desired manner, in the present instance a handle 20 being provided for manual operation. It. is to be understood that this shaft may be rotated in the' usual ways such for example as from-the fly-wheel of an engine or from a small electric motor.

From the foregoing description it will be seen that the rotation of the operating shaft and toothed cogs, results through contact of the latter with the diaphragm anvils, in the production of a sound or signal which is emitted through the horn projector.

If the periodicity of two diaphragms is the same they may be actuated by a single cog. In such a case whether one or two cogs are used I prefer to so arrange the parts that one of the diaphragms will cause an impulse of air to be thrown outward at the same time the other diaphragm is having a like effect, so that the resultant will be an amplified sound wave. Since the periodicity or rapidity of vibration of a diaphragm, and hence the pitch of the note produced, depends upon the number of teeth on the contacting cog and the speed of rotation of the latter, any desired note may be produced by providing that number of teeth which, at the usual and intended speed of operation, will ecure the necessary frequency ofvibration of the each diaphragm'will be vibrated at the samerate of speed and one note produced. However in many instances it will be considered preferable toprovide one cog with a smaller number of teeth than the other and, two diflerent notes will be produced. By observing the necessary ratio between the number of teeth on one cog and the greater or smaller number of teeth on the second cog, the vibrations of the diaphragms may be so coordinated that the different notes produced will be in harmony. In this manner either any single desired note may be produced, or any desired two notes in harmony. It is also important to so proportion the-air passages and the resonator, that they will amplify or augment the sound waves.

What I claim is: v

1. Ina horn or signal, a plurality of diaphragms and means for actuating the diaphragms to cause vibration thereof, said means comprising a plurality of toothed wheels, each wheel actuating a different diaphragm and the number of teeth on one wheel being greater than and in predetermined ratio to the number of teeth on a second wheel, means for rotating said wheels at the sameaspeed to impart to said diaphragms vibrations of different periodicities, and a projector receiving sound waves from both diaphragms.

2. In a horn or signal, two oppositely disposed substantially parallel diaphragms, a curved tube having the opposite ends -facing toward each other and closed by said diaphragms, a resonator connected with said phragm. a

4. In a horn or signal, two oppositely disj tube intermediate of its ends and means actuating said diaphragms, said means including two rotors rotatable about a common axis and operating to give a different number of vibrations to said'diaphragms.

3. In a horn or signal, two oppositely disposed. substantially parallel diaphragms, a curved tube having the opposite endsfacing toward each other and closed by said diaphragms, a resonator connected with said tube intermediate of its ends and means actuating said diaphragms, said means including two rotors rotatable about a common axis and each engaging witha diiferentdiaposed substantially parallel diaphragms, a curved tube having the opposite ends facing toward each other and closed by said diaphragms, a resonator connected with said tube intermediate of its ends and means actuating said diaphragms, said means including two rotors rotatable about a common axis and each engaging with a different diaphragm and having different numbers of teeth thereon.

In witness whereof, I have hereunto set iny hand this 30 day of January in the year ALDEN L. MOMURTRY. Witnesses: v I,

F. GRAVES, G. QUIMBY, 

